Safety device for boilers.



. "PATENTED AUG. 23, 1904.

. P. J. LOGKWOOD. SAFETY DEVICE' FUR BoILERs.

APPLICATION FILED DBC.11, 1903.

N0 MODEL.

Patented August 23, 1904.

QUNITED .STATES PATENT OFFICE...1

PHILO J. LOCKWOOD, WASHINGTON, DISTRICT OF COLUMBIA.

SAFETY DEVICE EORBQILERS,

SPECIFICATION forming part of lLettersPatent No.`768,383, dated August 23, 1904. Application filed December v11, 1903. Serial No. 184,804. (No model.)

.To a/ZZ whom t mfr/y concern:

Be it known that I, PHILO J. LooKWooD, a citizen of the United States, residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Safety Devices for Boilers, of which the following is a specification.

This invention relates to safety devices having for their object to permit the escape of steam from the boiler or a pipe or chamber connected with the boiler whenever the level of the water descends below a predetermined point, thereby preventing the evaporation of the water to a dangerously small quantity, the escaping steam serving as a means of giving notice of the dangerously low condition of the water or being availed of inany other suitable manner to prevent injuryfrom such low condition.

Heretofore fusible plugs intended for fusion by the heat of the steam have been employed, melting at a comparatively low temperature to permit the escape of steam when the water reaches a predetermined point, but in such manner as to result in uncertain and undesirable actions. In most instances the fusible plug has been in immediate Contact with a support that is contiguous to a large amount of incasing metal, and while the plug may be quickly melted when the steam at high pressure and high temperature is brought in contact with the same it is not fused when the steam is at a low pressure and low temperature because of the rapid convection of the heat away from the plug by the mass `of metal lwith which the plug is in contact. It follows, therefore, that the operation of the fusible plug insuch cases is eectedby the great variations in the heat of the steam, depending upon the change of pressure and that `the fusing of the alloyinstead of being directly and positively influenced by the temperature of the steam as it flows from the boiler is dependent upon and largely influenced by the mass of surrounding metal and thevariations in its action in conducting the heat away, de-

pending upon its exposure to cold winds and other conditions. The range of action, there- 4when the plug melts.

greatly impaired, if notwholly lost. Again, where a fusible plug is arranged as heretofore, the blowing off of the boiler, bringing the steam', if at a sufficient] y hi gh temperature, in contact with the plug, will melt and blow yaway the latter and necessitate its replacement. To obviate these defects, Iisolate the plug from the metal of the support by supporting the plug in a position distant from saidsupport, so that there can be no rapid convection of the heat fromA the plug to the support, as fully set forth hereinafter and as illustrated in the accompanying drawings, in

Which- Figure l illustrates in section a boiler, a pipe communicating therewith and showing 'one position in which my safety device may be applied thereto. Fig. 2 is a sectionof the `safety device detached and `provided with a valve which when used in a vertical position -serves to prevent the escape ofthe fusible alloy vwhen the boiler is blown off; Fig. 3, a viewv fuse under the presence of steam at any pres-Y sure at which it is liable to exist in the boiler. There is also a holder for this fusible plug, channeled to permit the passage of steam As shown, the holder is a long thin hollow tube or stem and for the purpose of ready attachment and removal this stem may extend from a block or plug o, which may screw into a threaded socket in the end of any suitable support-as, for instance, a pipe D, extending from the boiler TOO constituting the support for the device-as, for instance, the tube D-that the heat imparted on the access of steam to the plug will not pass to the .bod y of metal and be conveyed from the plug, which will be quickly fused.

To prevent the blowing out of the fusible plug when the water is blown off from the boiler and the steam obtains access to the plug, I in such case apply the device to a vertical support or pipe D' and make use of a valve A, Fig. 2, having a threaded stem the upper end of which closes against a valveseat below the socket holding the plug. When this valve is in place in a vertical position and the boiler is blown off, the plug, even if fused, is retained in its socket and hardens after the escape of the steam, when the valve A can be removed.

In some instances it is not desirable to be obliged to detach the valve A in order that the plug may operate, and in this case the valve-stem, as shown in Fig. 3, is less in diameter than the interior of the tubular stem b, which is open at the lower end. Thus it communicates at the lower end with ports c' in the block c, to which ports the steam mayl pass when the valve is turned, so as to carry its upper end from the valve-seat. Vhen the valve is turned to close against said seat, the plug will be retained in its socket even if melted.

It will be evident that the block c, supporting the holder and the fusible plug, may be so constructed as to be readily attached in any place where it may be desired to so support a fusible plug that it will be acted upon by heat without those variations of operation which would result when .the fusible plug is in direct contact with the mass of metal constituting the supporting-tube, casing, or other support.

Without limiting myself to the precise construction shown, I claim as my inventionl. A safety device provided with a channeled holder for a fusible plug arranged to be free from direct contact with the support to which the device may be applied, substantially as set forth.

2. The combination in a safety device for l steam-boilers, of a hollow stem having a socket for a fusible plug, and means for sustaining said stem in a position isolated from a support communicating with a boiler, substantiall, as set forth.

3. A safety device for steam-boilers consisting of a block adapted for attachment to a support communicating with a boiler, and a channeled stem supported by the block and having a socket for a fusible plug at the outer end, substantially as. set forth.

'4. A safety device for steam-boilers consisting of a block adapted for attachment to a support communicating with a boiler, a chan neled stem supported by the block and having a socket for a fusible plug at the outer end, and a valve for closing the bottom of said socket, substantially as set forth.

5. The combination in a safety device 'for boilers, of a perforated block, a channeled stem extending therefrom and provided with a socket for a fusible plug at the outer end, and a valve for closing the communication between the socket and the opening in the block, substantially as set forth.

6. The combination with a steam-boiler, of a channeled support communicating with the boiler, and a safety device attached to said su pport and provided with a holder for a fusible plug arranged out of contact with said support, substantially as set forth.

7. The combination with a boiler, of a channeled support communicating therewith, and a channeled stem supported within but free from contact with said support and having a socket for a fusible plug, substantially as set forth.

8. The combination with a channeled support communicating with a boiler, of a hollow stem supported within and out of contact with the support and having a socket for a fusible plug, substantially as set forth.

In testimony whereof I have signed n 1 y name to this specification in the presence of two suhscribing witnesses.

PHIL() J'. LOCKW'OOD.

Titnessesz CHARLES E. Fos'rnn, UA1-:L J. Lookwoop. 

